Smoking Articles Having Reduced Ignition Proclivity Characteristics

ABSTRACT

Smoking articles having reduced ignition proclivity characteristics are disclosed. The smoking articles include a paper wrapper containing cellulosic fibers and filler particles. The paper wrappers are treated with a film-forming composition in order to reduce the ignition proclivity characteristics of the smoking articles. In one embodiment, the film-forming composition contains an alginate combined with a starch. In an alternative embodiment, the film-forming composition contains a film-forming material combined with filler particles. The filler particles may comprise kaolin clay, magnesium oxide, mica, alum, or mixtures thereof.

RELATED APPLICATION DATA

The present application is based on and claims priority to a provisionalapplication filed on Jul. 3, 2007 having Ser. No. 60/958,263.

BACKGROUND

There is an ongoing concern in the tobacco industry to producecigarettes having wrappers which reduce the ignition proclivity of thesmoking article, or the tendency of the smoking article to ignitesurfaces which come into contact with the lit smoking article. Reportshave been made of fires attributed to burning cigarettes coming intocontact with combustible materials. A justifiable interest exists in theindustry to reduce the tendency of cigarettes, or other smoking articlesto ignite surfaces and materials used in furniture, bedding, and thelike upon contact.

Thus, a desirable feature of smoking articles, particularly cigarettes,is that they self-extinguish upon being dropped or left in a freeburning state in contact with combustible materials.

It has long been recognized in the tobacco industry that the cigarettewrapper has a significant influence on the smolder characteristics ofthe cigarette. In this regard, various attempts have been made in theart to alter or modify the cigarette wrappers in order to achieve thedesired tendency of the cigarette to self-extinguish, or in other wordsto reduce the ignition proclivity characteristics of cigarettes.

The prior art describes the application of film-forming solutions tocigarette paper to reduce the paper permeability and control the burnrate. It has been shown that when these materials have been applied indiscrete areas along the length of the cigarette, the cigarette shows areduced propensity to ignite a substrate, and tends to self-extinguish.

U.S. Pat. No. 5,878,753 to Peterson and U.S. Pat. No. 5,820,998 toHotaling, et al. which are incorporated herein by reference, forexample, describe a smoking article wrapper being treated with afilm-forming aqueous solution to reduce permeability. U.S. Pat. No.5,878,754 to Peterson which is also incorporated herein by referencedescribes a smoking article wrapper being treated with a non-aqueoussolution of a solvent soluble polymer dissolved in a non-aqueoussolution to reduce permeability.

The present application is directed to further improvements in producinga wrapper for a smoking article with reduced ignition proclivityproperties. In particular, the present disclosure is directed toimproved formulations that may be applied to the paper wrapper.

SUMMARY

The present disclosure is generally directed to paper wrappers forsmoking articles with reduced ignition proclivity and to a process formaking the wrappers. For example, in one embodiment, the paper wrappercan be made from a paper web. For example, the paper wrapper can containflax fibers, softwood fibers, hardwood fibers and mixtures thereof. Thepaper wrapper can also include a filler, such as calcium carbonateand/or a magnesium oxide, in an amount from about 10% to about 40% byweight.

A film-forming composition is applied to the paper wrapper at particularlocations. The film-forming composition forms treated discrete areas onthe wrapper. The discrete areas are separated by untreated areas. Thetreated discrete areas are configured to reduce ignition proclivity of asmoking article incorporating the wrapper. For example, the treatedareas can reduce ignition proclivity by reducing oxygen to a smolderingcoal of the smoking article as the coal burns and advances into thetreated areas.

In one embodiment of the present disclosure, the film-formingcomposition comprises the combination of a film-forming material, whichmay itself be a polysaccharide, and a polysaccharide, such as a starch,which may also be considered a film-forming material. It has beenunexpectedly discovered that combining a film-forming material with astarch produces synergistic results. In particular, a film-formingcomposition containing both a film-forming material and a starch hasbeen found to be more efficient at reducing the ignition proclivitycharacteristics of a smoking article in comparison to a film-formingcomposition containing a film-forming material alone or a film-formingcomposition containing a starch alone.

The film-forming material combined with the starch in accordance withthe present disclosure can vary depending upon the particularapplication. Film-forming materials that may be used include, forinstance, guar gum, pectin, polyvinyl alcohol, polyvinyl acetate,cellulose, cellulose derivatives such as ethyl cellulose, methylcellulose, hydroxypropyl cellulose, hydroxyethyl cellulose,carboxymethyl cellulose, and the like, alginates, and mixtures thereof.In one particular embodiment, for instance, a starch may be combinedwith an alginate in forming the composition.

The relative amounts of the starch and film-forming material, such asalginate, within the film-forming composition may vary depending uponthe particular application. In one embodiment, for instance, thefilm-forming material may be present within the film-forming compositionafter being applied and dried on a paper wrapper in an amount from about1% to about 15% by weight of the treated areas. Starch, on the otherhand, may be present in the treated areas in an amount from about 1% toabout 20% by weight of the treated areas.

In another embodiment of the present disclosure, the film-formingcomposition contains a film-forming material combined with specificfiller particles.

The filler particles may comprise, for instance, magnesium oxide, mica,kaolin clay, or mixtures thereof. In the past, those skilled in the arthave suggested combining a film-forming material with variousparticulate inorganic fillers. The present inventors have discovered,however, that the above fillers are unexpectedly more efficient atreducing the ignition proclivity properties of a treated paper wrapperin comparison to the particulate inorganic fillers used in the past.

The above listed filler particles may be contained in the film-formingcomposition (as applied to the wrapper) in an amount from about 0.25% toabout 15% by weight of the composition, such as from about 0.5% to about5% by weight of the composition. The filler particles can have anaverage diameter from about 0.0001 microns to about 5 microns, such asfrom about 0.1 microns to about 3 microns.

The film-forming material combined with the filler particles can be anysuitable film-forming material such as an alginate. In an alternativeembodiment, the filler particles can be combined with a starch. In stillanother embodiment, the filler particles may be combined with afilm-forming composition containing both an alginate and a starch.

Other film-forming materials that may be used solely or in combinationwith the filler particles include guar gum, pectin, polyvinyl alcohol,polyvinyl acetate, cellulose and cellulose derivatives such as ethylcellulose, methyl cellulose, hydroxypropyl cellulose, hydroxyethylcellulose, carboxymethyl cellulose, and the like.

The film-forming composition made according to the present disclosurecan be applied to the paper wrapper according to various methods. Forexample, the composition can be printed onto the paper using, forinstance, flexography, direct gravure printing, and offset gravureprinting.

In one embodiment, the discrete areas formed by the film-formingcomposition are in the shape of circumferential bands disposedlongitudinally along the smoking article. The bands can have a width ofgreater than about 3 mm, such as from about 4 mm to about 10 mm. Thebands can be spaced from each other at a distance of from about 5 mm toabout 50 mm and particularly from about 10 mm to about 40 mm.

The amount of the film-forming composition that is applied to the paperwrapper depends upon the particular application and various factors. Forexample, the film-forming composition can be applied to the wrapper inan amount from about 1% to about 30% by dry weight based upon the weightof the wrapper within the treated areas, and particularly in an amountfrom about 2% to about 20% by dry weight.

Once applied to the paper wrapper, the treated areas can have apermeability of less than about 40 Coresta, particularly less than about30 Coresta, and more particularly from about 1 Coresta to about 30Coresta. The initial permeability of the paper wrapper can be from about20 Coresta to about 150 Coresta or greater. For example, in oneembodiment, the initial permeability of the paper wrapper may be greaterthan about 60 Coresta, such as greater than about 80 Coresta. In analternative embodiment, the initial permeability of the paper wrappermay be less than about 60 Coresta, such as from about 20 Coresta toabout 40 Coresta.

The film-forming composition when applied to the paper wrapper may becontained in an aqueous solution or may be contained in a non-aqueoussolution. When contained in a non-aqueous solution, for example, analcohol may be present.

The paper wrapper may have any suitable basis weight depending upon aparticular application. In one particular embodiment, for instance, thepaper wrapper may have a basis weight of from about 18 gsm to about 60gsm. The paper wrapper may also be treated with a burn promoting agentover substantially the entire surface area of the paper wrapper. Forexample, the burn promoting agent may be applied to the paper wrapperprior to or after the treated areas are formed. The burn promoting agentmay be applied to the paper wrapper in amounts from about 0.1% to about8% by dry weight. The burn promoting agent may be, for instance, anacetic acid salt, a citric acid salt, a malic acid salt, a lactic acidsalt, a tartaric acid salt, a carbonic acid salt, a formic acid salt, apropionic acid salt, a glycolic acid salt, a fumaric acid salt, anoxalic acid salt, a malonic acid salt, a succinic acid salt, a nitricacid salt, a phosphoric acid salt, or mixtures thereof. In oneparticular embodiment, the burn promoting agent is a citrate, asuccinate, or mixtures thereof.

Other features and aspects of the present disclosure are discussed ingreater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present disclosure, including thebest mode thereof to one of ordinary skill in the art, is set forth moreparticularly in the remainder of the specification, including referenceto the accompanying figures in which:

FIG. 1 is a perspective view of a smoking article made in accordancewith the present disclosure;

FIG. 2 is an exploded view of the smoking article illustrated in FIG. 1;and

FIGS. 3-8 are graphical representations of the results obtained in theexamples that follow.

Repeat use of reference characters in the present specification anddrawings is intended to represent same or analogous features or elementsof the present disclosure.

DETAILED DESCRIPTION

Reference now will be made in detail to the embodiments of thedisclosure, one or more examples of which are set forth below. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe disclosure. For instance, features illustrated or described as partof one embodiment, can be used on another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncover such modifications and variations.

For purposes of explanation of the disclosure, the embodiments andprinciples of the disclosure will be discussed in regards to acigarette. However, this is for the purposes of explanation of thedisclosure only and is not meant to limit the disclosure only tocigarettes. Any manner of smoking article is within the scope and spiritof the disclosure.

The present disclosure relates to a smoking article and a wrapper for asmoking article having improved ignition proclivity controlcharacteristics. “Ignition proclivity” is a measure of the tendency ofthe smoking article or cigarette to ignite a flammable substrate if theburning cigarette is dropped or otherwise left on a flammable substrate.A test for ignition proclivity of a cigarette has been established byNIST (National Institute of Standards and Technology) and is generallyreferred to as the “Mock-Up Ignition Test”. The test comprises placing asmoldering cigarette on a flammable test fabric and recording thetendency of the cigarette to either ignite the test fabric, burn thetest fabric beyond a normal char line of the fabric, burn its entirelength without igniting the fabric, or self-extinguish before ignitingthe test fabric or burning its entire length.

Another test for ignition proclivity is referred to as the “CigaretteExtinction Test”. The Cigarette Extinction Test is ASTM Test No.E2187-04. In the Cigarette Extinction Test, a lit cigarette is placed onone or more layers of filter paper. If the cigarette self extinguishes,the cigarette passes the test. If the cigarette burns all the way to itsend on the filter, however, the cigarette fails. Smoking articles madein accordance with the present invention can be designed to pass one orboth of these tests.

In addition to the above tests, smoking articles having reduced ignitionproclivity cigarettes are typically also tested for “free airself-extinguishment” (FASE). During the free air extinguishment test,the smoking articles are allowed to burn in the free air without beingpuffed and without being placed on an adjacent surface. In someapplications, it is desirable for a smoking article to pass the mock upignition test or the cigarette extinction test while notself-extinguishing when left burning in the free air. Thus, lower FASErates may be preferred. Of particular advantage, smoking articlesconstructed in accordance with the principles of the present disclosuremay be configured to self extinguish when placed on an adjacent surfacebut yet have lower FASE rates in comparison to many prior products thatare intended to have reduced ignition proclivity characteristics.

In general, smoking articles having reduced ignition proclivity are madeaccording to the present disclosure by applying in discrete areas to awrapping paper a film-forming composition. In one embodiment, thefilm-forming composition contains a film-forming material combined witha polysaccharide. The film-forming material may comprise, for instance,an alginate, guar gum, pectin, polyvinyl alcohol, polyvinyl acetate,cellulose, a cellulose derivative, or mixtures thereof. Thepolysaccharide may comprise, for instance, a starch. The starch may be anatural starch or may be a modified starch. The present inventors havediscovered that when a polysaccharide and a film-forming material arecombined together, various synergistic advantages and benefits areobtained.

In the past, the assignee of the present application has obtainedvarious patents directed to smoking articles with reduced ignitionproclivity characteristics. For example, paper wrappers treated with afilm-forming composition that forms treated discrete areas on thewrapper are disclosed in U.S. Pat. Nos. 5,878,753; 5,878,754; 6,568,403;6,779,530 and 6,725,867, which are incorporated herein by reference. Theabove patents disclose various different film-forming materials that maybe used to form the treated discrete areas. In particular, the abovepatents disclose the use of alginate and disclose the use of starch. Thepresent inventors, however, have found that various unexpected benefitsand advantages are obtained when starch and a film-forming material suchas an alginate are combined together.

For instance, although the rheology of starch and alginate aredifferent, it has been discovered that the rheology of the twocomponents are complimentary. When starch and alginate are combined, forinstance, the resulting solution has improved printability.

The combination of a film-forming material such as an alginate andstarch has also provided various efficiency improvements in the abilityof the solution to form treated areas on paper wrappers that reduce theignition proclivity characteristics of a smoking article incorporatingthe wrapper. In particular, on a weight basis, an alginate and starchsolution is generally more efficient in lowering the permeability anddiffusion capacity of the paper wrapper in comparison to a similarsolution containing only starch or only alginate.

Although any film-forming material may be used in the composition inaccordance with the present disclosure, in one embodiment, thefilm-forming material comprises an alginate. In general, an alginate isa derivative of an acidic polysaccaride or gum which occurs as theinsoluble mixed calcium, sodium, potassium and magnesium salt in thePhaeophyceae brown seaweeds. Generally speaking, these derivatives arecalcium, sodium, potassium, and/or magnesium salts of high molecularweight polysaccarides composed of varying proportions of D-mannuronicacid and L-guluronic acid. Exemplary salts or derivatives of alginicacid include ammonium alginate, potassium alginate, sodium alginate,propylene glycol alginate, and/or mixtures thereof.

Any suitable alginate may be used in the present disclosure, includingany suitable derivatives. The alginate contained in the film-formingcomposition, for instance, may have a relatively high molecular weightor may have a relatively low molecular weight. For example, in oneembodiment, the alginate may have a viscosity of less than about 500 cPwhen contained in a 3% by weight aqueous solution at 25° C.

In one embodiment, for instance, KELGIN LB alginate from ISP Corporationmay be used. KELGIN LB alginate is a low viscosity, pure sodiumalginate.

The polysaccharide that is combined with the alginate in accordance withthe present disclosure may also vary depending upon the particularapplication. When using a starch, the starch, for instance, may bemodified or may be unmodified and may be obtained from various plants.In one embodiment, for instance, an oxidized corn starch may be combinedwith the alginate. One example of a commercially available oxidized cornstarch is FLOKOTE 64 commercially available from the National Starch andChemical Company of Bridgewater, N.J.

When formulated into a film-forming composition and applied to a paperwrapper in accordance with the present disclosure, the film-formingmaterial and polysaccharide can be combined with water or with anysuitable solvent. For instance, in one embodiment, the film-formingcomposition may comprise an aqueous dispersion or an aqueous solution.Alternatively, the film-forming composition prior to being applied tothe paper wrapper may comprise a non-aqueous solution or dispersion. Forinstance, an alcohol may be present and combined with the film-formingmaterial and polysaccharide.

The amount of the film-forming material and polysaccharide presentwithin the film-forming composition may depend upon various factors.When formulating an aqueous solution or dispersion, for instance, thefilm-forming material such as an alginate may be present in thefilm-forming composition in an amount from about 1% to about 15% byweight of the solution, such as from about 1% to about 10% by weight ofthe solution. For instance, in one embodiment, alginate may be presentin an amount from about 1% to about 10% by weight of the solution.Starch, on the other hand, may be present in an amount from about 3% toabout 25% by weight of the solution, such as from about 3% to about 20%by weight of the solution. For instance, in one embodiment, starch maybe present in the film-forming composition in an amount from about 3% toabout 15% by weight of the solution.

It should be understood that the above percentages are merely exemplary.When printing the film-forming composition onto a paper wrappercontaining a film-forming material and polysaccharide, the film-formingmaterial and polysaccharide can be contained in the composition inamounts sufficient so that the composition has Theological propertiesthat make the composition amenable to a printing process. For instance,the relative amounts of film-forming material and polysaccharide can bepresent in the composition so that the composition has a viscosity ofless than about 1500 cps.

Although unknown, it is believed that when a film-forming material and apolysaccharide are combined together, both components form a film on thesurface of the paper that is well suited to extinguishing a smokingarticle should the article be left on an adjacent surface. Althoughunknown, it is believed that the film-forming material is better suitedto forming a film on the wrapper while the polysaccharide maintains alower viscosity and improves the properties of the treated areas. Onceapplied to the paper wrapper and dried, the treated areas may contain,in one embodiment, a greater amount of polysaccharide than film-formingmaterial. In other embodiments, however, the polysaccharide and thefilm-forming material may be present in equal amounts or a greateramount of the film-forming material may be present. In general, forinstance, the treated areas may contain a polysaccharide from about 1%to about 20% by dry weight of the treated area, while containing thefilm-forming material in an amount from about 1% to about 15% by dryweight of the treated area.

In an alternative embodiment of the present disclosure, the film-formingcomposition applied to the paper wrapper contains a film-formingmaterial combined with filler particles. Specifically, the presentinventors have discovered that certain filler particles provideunexpected advantages in improving the ignition proclivitycharacteristics of the wrapper in comparison to filler particles thathave been proposed in the past. Specifically, in this embodiment of thepresent disclosure, the film-forming composition can contain magnesiumoxide particles, kaolin clay particles, mica particles, or mixturesthereof.

In the past, such as in U.S. Pat. No. 6,725,867, those skilled in theart have proposed to combine a particulate filler into a compositionused to form treated areas on a cigarette wrapping paper. In the '867patent, for instance, the particulate filler is described as beingchalk, clay, calcium carbonate or titanium oxide. The present inventors,however, have discovered that the above listed particles, as shown inthe examples below, demonstrate unexpectedly superior results incomparison to the fillers listed in the '867 patent.

The magnesium oxide, mica, or kaolin clay may be present in thefilm-forming composition, for instance, in an amount less than about 15%by weight, such as from about 0.25% to about 15% by weight, andparticularly, from about 0.5% to about 5% by weight. In manyapplications, for instance, the particles can be present in an amountfrom about 1% to about 3% by weight of the composition.

The size of the filler particles may vary depending upon the particularmaterial used in the particular application. In general, the fillerparticles have an average diameter of less than about 5 microns. Forinstance, the average size of the particles may be from about 0.0001microns to about 5 microns, such as from about 0.1 microns to about 3microns. The shape of the particles may also vary. For instance, in oneembodiment, kaolin clay particles may be used that have a plate-likeshape.

As described above, in one embodiment, the filler particles comprisemagnesium oxide particles. Although the reason is unknown, magnesiumoxide particles provide superior results in comparison to many otherfiller particles. In particular, magnesium oxide particles have theability to efficiently reduce the ignition proclivity properties of asmoking article containing a treated wrapper.

In general, any suitable magnesium oxide particles may be used in thefilm-forming composition. Magnesium oxide particles, for instance, areavailable from numerous commercial sources. For instance, in oneembodiment, magnesium oxide particles may be used that are commerciallyavailable from Additek S.A.S. under the name Magnesium Oxide Super LegerType 04. Magnesium oxide particles well suited for use in the presentdisclosure are also obtainable from Scora S.A. under the name LightMagnesium Oxide “I”. The Light Magnesium Oxide “I” particles, forinstance, are greater than 98% by weight magnesium oxide, have a bulkdensity of from about 0.15 g/cc to about 0.2 g/cc and have a particlesize such that about 98% of the particles pass through a 325 mesh sieve.

In another embodiment, the filler particles contained within thefilm-forming composition may comprise mica. Mica comprises a group ofminerals consisting of hydrous silicates of aluminum or potassium whichare common in igneous and metamorphic rocks. Mica is typically found ingroups of sheet silicate minerals having a highly perfect basalcleavage. Thus, mica particles when incorporated into a film-formingcomposition typically have a plate-like shape. Mica has a highdielectric strength and therefore is resistant to heat.

Mica particles are commercially available from numerous sources. Forinstance, mica particles that are well suited for use in the presentdisclosure are obtainable from Kaolins de Ploemeur under the trade nameMICA MU M2/1. MICA MU M2/1, for instance, has a particle size such thatgreater than about 50% of the particles have a size less than about 5microns.

In another embodiment of the present disclosure, the film-formingcomposition may contain kaolin clay particles. Kaolin clay is generallya hydrous aluminum silicate mineral found in sediments, soils,hydrothermal deposits and sedimentary rocks. Kaolin clay particles canhave a plate-like shape typically being found as a layered silicatemineral. Kaolin clay particles typically contain silicon dioxide andaluminum oxide.

Kaolin clay particles are available from numerous commercial sources.For instance, kaolin clay particles can be obtained from Kaolins dePloemeur under the trade name 7ASP20. 7ASP20 kaolin clay, for instance,has a particle size such that greater than 89% of the particles have asize less than 5 microns and greater than about 64% of the particleshave a size less than about 1 micron.

The filler particles as described above, when contained in thefilm-forming composition, can be combined with any suitable film-formingmaterial. For instance, in one embodiment, the filler particles may becombined with an alginate and a starch as described above. In otherembodiments, however, the filler particles may be combined with alginatealone or with starch alone.

Other film-forming materials that may be combined with the fillerparticles include guar gum, pectin, polyvinyl alcohol, polyvinylacetate, cellulose, cellulose derivatives such as ethyl cellulose,methyl cellulose, and carboxymethyl cellulose, hydroxypropyl cellulose,hydroxyethyl cellulose, mixtures thereof, and the like.

Prior to application to the wrapper, the film-forming compositioncontaining the filler particles may be water based. Alternatively, thefilm-forming composition may contain a non-aqueous solvent, such as analcohol.

Film-forming compositions made according to the present disclosure,including film-forming compositions containing alginate and starchand/or film-forming compositions containing filler particles, can beapplied to paper wrappers in discrete areas to form treated areas on thewrapper.

The manner in which the composition is applied to the paper wrapper canvary. For example, the composition can be sprayed, brushed or printedonto the wrapper. To form a treated area, the composition can be appliedin a single pass or in a multiple pass operation. For instance, thecomposition can be applied to the wrapping paper in successive steps inorder to form areas on the paper having reduced ignition proclivity. Ingeneral, during a multiple pass process, the treated areas can be formedby applying the composition during from about 2 to about 8 passes.

In order to assist in describing and explaining the present disclosure,one embodiment is illustrated generally in FIGS. 1 and 2. A smokingarticle (cigarette), generally 10, having improved ignition proclivitycharacteristics includes a tobacco column 12 within a wrapper 14.Article 10 may include a filter 26. Wrapper 14 may include any manner ofcommercially available cigarette wrapper.

Generally, the wrapping paper can be made from cellulosic fibersobtained, for instance, from flax, softwood or hardwood. In order tovary the properties of the paper as desired, various mixtures ofcellulosic fibers can be used. The extent to which the fibers arerefined can also be varied.

For most applications, the paper wrapper will contain a filler. Thefiller can be, for instance, calcium carbonate, magnesium oxide, or anyother suitable material. The total filler loading added to the paperwrapper can be between about 10% to about 40% by weight.

The permeability of a paper wrapper for smoking articles made accordingto the present disclosure can generally be from about 10 Coresta unitsto about 200 Coresta units. In some applications, the permeability canbe between about 15 Coresta units to about 55 Coresta units. In oneembodiment of the present disclosure, however, the initial permeabilityof the paper wrapper is relatively high. For instance, in oneembodiment, the permeability of the paper wrapper can be from about 60Coresta units to about 110 Coresta units. In various embodiments, forexample the initial permeability of the paper wrapper may be greaterthan about 70 Coresta units, greater than about 80 Coresta units,greater than about 90 Coresta units, or greater than about 100 Corestaunits.

In other embodiments, the initial permeability of the paper wrapper maybe less than about 60 Coresta units, such as less than about 50 Corestaunits, such as from about 20 Coresta units to about 40 Coresta units.

The basis weight of cigarette wrapping paper is usually between about 18gsm to about 60 gsm, and more particularly between about 15 gsm to about40 gsm. Wrapping papers according to the present disclosure can be madewithin any of these ranges.

In one embodiment, the paper wrapper may be treated with a burnpromoting agent. The burn-promoting agent, for example, may be appliedover substantially the entire surface area of the wrapping paper,especially over the surface area of the wrapping paper where the treatedareas are located including the untreated areas spaced between thetreated areas. The burn promoting agent may comprise any suitablesubstance that enhances the burn rate. Examples of burn promoting agentsinclude alkali metal salts, alkaline earth metal salts, and mixturesthereof. In one embodiment, the burn promoting agent may comprise a saltof a carboxylic acid. In particular examples, for instance, the burnpromoting agent may comprise an acetic acid salt, a citric acid salt, amalic acid salt, a lactic acid salt, a tartaric acid salt, a carbonicacid salt, a formic acid salt, a propionic acid salt, a glycolic acidsalt, a fumaric acid salt, an oxalic acid salt, a malonic acid salt, asuccinic acid salt, a nitric acid salt, a phosphoric acid salt, andmixtures thereof. In one particular application, for instance, the burnpromoting agent may comprise potassium citrate, sodium citrate,potassium succinate, sodium succinate, or mixtures thereof.

The burn promoting agent may be applied relatively uniformly over thesurface area of the paper wrapper in an amount from about 0.3% to over8% by dry weight, such as from about 0.3% to about 2.5% by dry weight.The burn promoting agent may be applied to the wrapper prior to or afterthe treated areas are formed on the wrapper using the film formingcomposition.

The burn promoting agent may be applied to the wrapper for variousreasons. For example, the burn promoting agent may be applied so as tofurther control the burn properties of the wrapper, especially in theuntreated areas on the wrapper. The burn promoting agent may also serveas an ash conditioner.

Paper web 14 defines an outer circumferential surface 16 when wrappedaround tobacco column 12. Discrete areas 18 of outer circumferentialsurface 16 are treated with a film-forming composition made inaccordance with the present invention, such as an alginate compositionblended with a burn promoting agent. It should also be understood thattreated areas 18 could also be disposed on the inner surface of wrapper14. In other words, wrapper 14 could be rolled around tobacco column 12so that treated areas 18 are adjacent to the tobacco.

In the embodiment illustrated in FIGS. 1 and 2, treated areas 18 aredefined as circumferential cross-directional bands 24. Bands 24 arespaced apart from each other longitudinally along the length ofcigarette 10. The bands 24 are indicated in phantom in FIG. 2. However,it should be understood that the treated areas are essentially invisiblein the formed cigarette as shown in FIG. 1. In other words, a smoker maynot discern from any outward sign that the wrapper 14 has been treatedin discrete areas 18. In this regard, treated areas 18 have a smooth andflat texture essentially the same as untreated areas 28.

The width and spacing of bands 24 are dependent on a number ofvariables, such as the initial permeability of wrapper 14, density oftobacco column 12, etc. The bands 24 preferably have a width so thatoxygen is limited to the burning coal for a sufficient length or periodof time to extinguish the coal. In other words, if band 24 were toonarrow, the burning coal would burn through band 24 beforeself-extinguishing. For most applications, a minimum band width of 3 mmis desired. For example, the band width can be from about 4 mm to about10 mm.

The spacing between bands 24 is also a factor of a number of variables.The spacing should not be so great that the cigarette burns for asufficient length of time to ignite a substrate before the coal everburns into a treated area 18. The spacing between bands 24 also affectsthe thermal inertia of the burning coal, or the ability of the coal toburn through the treated bands 24 without self-extinguishing. In thecigarettes tested, applicants have found that a band spacing of between5 and 50 mm is appropriate and particularly between about 10 mm and 40mm. However, it should be understood that the band spacing can be anysuitable width as determined by any number of variables. For mostapplications, the smoking article can contain from 1 to about 3 bandsusing the above spacing.

Treated areas 18 have a permeability within a range which is known toprovide improved ignition proclivity characteristics for the make-up ofcigarette 10. As the coal of cigarette 10 burns into treated areas 18,oxygen available to the burning coal is substantially reduced due to thedecreased permeability of wrapper 14 in the treated areas. The reductionof oxygen preferably causes the cigarette to self-extinguish in thetreated areas 18 when in contact with a substrate. The permeability, forinstance, may be less than 40 ml/min/cm² (CORESTA), particularly lessthan 30 ml/min/cm², and generally within a range of 5 to 25 ml/min/cm².

Another property of the paper wrapper than can be used to indicatereduced ignition proclivity properties is diffusion capacity. Ingeneral, the treated areas 18 according to the present disclosure canhave a diffusion capacity of less than about 0.5 cm/s, such than about0.4 cm/s. For instance, the diffusion capacity can be from about 0 cm/sto about 0.3 cm/s.

Diffusion capacity of the paper wrapper, for instance, can be measuredusing, for instance, a carbon dioxide diffusion capacity tester that ismarketed by SODIM Instrumentation Company.

The above described diffusion capacity ranges are particularlyapplicable to characterizing treated areas made from a combination of afilm-forming material and a polysaccharide. In other embodiments of thepresent disclosure, such as when a film-forming material is combinedwith filler particles, the diffusion capacity may be higher than asdescribed above. In particular, the filler particles of the presentdisclosure when contained in the film-forming composition may reduce theignition proclivity properties of the paper because the particles areflame retardants. Thus, in some embodiments, the treated areas may havea diffusion capacity of higher than 0.5 cm/s.

The amount of composition that is added to the paper will depend uponvarious factors, including the type of composition that is used and thedesired result. For most applications, the film-forming composition canbe added to the paper in an amount from about 1% to about 30% by dryweight of the paper within the banded region, and particularly fromabout 2% to about 20% by dry weight of the paper within the bandedregion after the bands have been formed and dried. Although not alwaysthe case, generally the amount of the composition applied to the paperwill generally increase as the permeability of the paper increases. Forinstance, for wrapping papers having a permeability of less than about30 Coresta units, the composition can be applied to a paper in an amountfrom about 1% to about 20% by weight. For wrapping papers having apermeability greater than about 60 Coresta units, on the other hand, thecomposition can be applied to the paper in an amount from about 3% toabout 30% by weight.

As described above, the composition can be sprayed, brushed, or printedonto the wrapper. In general, any suitable printing process can be usedin the present invention. Applicants have found that suitable printingtechniques include gravure printing, or flexographic printing.

The present disclosure may be better understood with reference to thefollowing examples.

EXAMPLE 1

Various paper wrappers were made containing cellulosic fibers incombination with a filler. In this example, the filler comprised calciumcarbonate having a medium particle size of 2 microns. The calciumcarbonate particles were present in the paper wrapper in an amount of30% by weight. The wrappers had a basis weight of 27 gsm and a basepermeability of 53 Coresta.

Various film-forming compositions were formulated and printed onto thepaper wrapper. In particular, the following film-forming compositionswere formulated.

-   -   1. Aqueous composition containing 1.5% by weight alginate.    -   2. Aqueous composition containing 10% by weight starch.    -   3. Aqueous composition containing 11.5% by weight starch.    -   4. Aqueous composition containing 8% by weight alginate.    -   5. Aqueous composition containing 11.5% by weight alginate.    -   6. Aqueous composition containing 1.5% by weight alginate and        10% by weight starch.

In this example, the alginate used was KELGIN LB obtained fromInternational Specialty Products. The starch used was an oxidized starchsold under the trade name FLOKOTE 64 obtained from the National Starchand Chemical Company.

After the above compositions were applied to the paper wrapper anddried, the permeability within the treated areas was measured andcompared to the untreated paper wrapper. The results are shown in FIG.3. As shown, the combination of alginate and starch was more efficientat reducing the permeability of the paper wrapper in comparison to theother compositions. In each case, the same amount of composition wasapplied to the paper wrapper.

EXAMPLE 2

In this example, various film-forming compositions were formulatedcontaining both sodium alginate and an oxidized starch. In particular,the same alginate and starch as described in Example 1 were used.

In one set of tests, the film-forming compositions were applied to apaper wrapper as described in Example 1 having a permeability of 53Coresta. In a second set of tests, the film-forming compositions wereapplied to a paper wrapper having a base permeability of 80 Coresta.

Specifically, the following film-forming compositions were formulated:

PERCENT BY WEIGHT PERCENT BY SAMPLE SODIUM ALGINATE WEIGHT OXIDIZEDVISCOSITY NO. (%) STARCH (%) (CPS) 1 3.2 15 180 2 4.75 11.3 210 3 6.37.5 270

The above film-forming compositions were applied to the paper wrapperusing the same process described in Example 1. The following resultswere obtained:

Results on Paper Wrapper Having a Base Permeability of 53 Coresta

PERMEABILITY WITHIN THE TREATED SAMPLE NO. AREAS (CORESTA) 1 13 2 13 315

Results on Paper Wrapper Having a Base Permeability of 80 Coresta

PERMEABILITY WITHIN THE TREATED SAMPLE NO. AREAS (CORESTA) 1 22 2 22 326

The 53 Coresta base paper containing Sample No. 3 and the 80 Corestabase paper containing Sample No. 1 were then wrapped around a column ofa tobacco filler. The resulting smoking articles were tested accordingto ASTM Test No. E2187-04 and according to the FASE Test. The followingresults were obtained:

BASE PERMEABILITY COMPOSITION ASTM SE (CORESTA) SAMPLE NO. FASE SE (%)(%) 53 3 10 100 80 1 10 95

As shown above, both of the smoking articles were very effective atself-extinguishing when placed on adjacent surface. Of particularadvantage, both smoking articles also had a low FASE rating indicatingthat smoking articles have a lower tendency to self-extinguish when leftin a free-burning state.

EXAMPLE 3

In this example, various filler particles were added to a sodiumalginate film-forming composition and applied to a paper wrapper. Inparticular, film-forming compositions were made containing kaolin clayparticles and magnesium oxide particles. These formulations were thencompared with film-forming compositions containing no particles andfilm-forming compositions containing calcium carbonate particles andtalc particles.

In particular, the following filler particles were added to an aqueoussolution containing 9.5% by weight sodium alginate. The sodium alginateused in this example was KELGIN LB sodium alginate obtained fromInternational Specialty Products.

SAMPLE NO. FILLER PARTICLES SOLUTION WEIGHT (%) 1 — — 2 TALC 15 3CALCIUM CARBONATE 15 (2 MICRONS) 4 CALCIUM CARBONATE 15 (1 MICRON) 5MAGNESIUM OXIDE 15 6 KAOLIN CLAY 15

The above film-forming compositions were applied to the same paperwrappers described in Example 2 above. In particular, the film formingcompositions were printed onto a paper wrapper having a basepermeability of 53 Coresta and a paper wrapper having a basepermeability of 80 Coresta. The permeability within the treated areaswas then measured after the film-forming compositions had dried on thepaper. The results are illustrated in FIG. 4.

As shown in FIG. 4, kaolin clay particles and magnesium oxide particlesunexpectedly reduced the permeability of the wrappers to a much greaterextent than the film-forming composition containing no filler particlesand in comparison to the film-forming compositions containing talc orcalcium carbonate.

EXAMPLE 4

In this example, different amounts of the same filler particles wereadded to a sodium alginate solution and tested.

Specifically kaolin clay particles and magnesium oxide particles wereadded to a 9.5% by weight sodium alginate composition. The sodiumalginate used was KELGIN LB sodium alginate obtained from theInternational Specialty Products. The following film-formingcompositions were formulated.

SAMPLE NO. FILLER WEIGHT (%) 1 NONE 0 2 KAOLIN CLAY 4 3 KAOLIN CLAY 8 4KAOLIN CLAY 13 5 MAGNESIUM OXIDE 10 6 MAGNESIUM OXIDE 5 7 MAGNESIUMOXIDE 4 8 MAGNESIUM OXIDE 3 9 MAGNESIUM OXIDE 2 10 MAGNESIUM OXIDE 1

The above film-forming compositions were then applied to the 80 Corestapaper wrapper described in the preceding examples. Various tests werethen conducted on the compositions and on the paper wrappers. Inaddition, some of the paper wrappers were made into smoking articles andtested. The results are illustrated in FIGS. 5-8.

FIG. 5, for instance, shows the permeability within the treated areasfor Sample Nos. 1-4 containing the kaolin clay particles. The viscosityof the film-forming compositions was also tested and appears in thegraph. As shown, the permeability of the treated areas decreases as theamount of kaolin clay particles increases.

Referring to FIG. 6, the effect of the amount of magnesium oxide in thefilm-forming composition on the permeability on the treated areas isshown. As illustrated, as the amount of magnesium oxide increases, thepermeability of the treated areas decreases. In FIG. 6, the amount ofmagnesium oxide in the film-forming composition varies from 0 to 4%.

Paper wrappers containing the various amounts of magnesium oxide werethen used to construct cigarettes that were tested according to ASTMTest No. E2187-04 and according to the FASE Test. The ASTM Test measuresthe ability of the treated areas to extinguish the cigarette when leftresting on an adjacent surface. A higher number is generally preferred.The FASE Test, on the other hand, evaluates whether or not the cigaretteself-extinguishes when left free-burning. Generally, a lower FASE resultis preferred but not necessary or critical. For many applications, forinstance, ASTM test results can be more important than the FASE results.

The results of these tests are illustrated in FIG. 7. As shown, thepresence of magnesium oxide within the film-forming composition improvesthe ASTM ranking. Increasing the amount of magnesium oxide within thefilm-forming composition, however, has a tendency to increase the FASEranking. As shown, when magnesium oxide particles are present within afilm-forming composition containing 9.5% by weight alginate, better FASEresults are achieved when magnesium oxide is present in an amount lessthan about 3% by weight.

Referring to FIG. 8, further FASE and ASTM results are shown for analginate composition containing no filler particles, for an alginatecomposition containing 5% by weight magnesium oxide particles, and foran alginate composition containing 10% by weight magnesium oxide. Asshown, the control formulation containing 9.5% alginate did not pass theASTM Test. It is believed that the permeability of the treated areas wastoo high.

EXAMPLE 5

In this example, magnesium oxide particles were added to an oxidizedstarch solution and applied to a paper wrapper with a base permeabilityof 60 Coresta.

Specifically 3% by weight magnesium oxide particles were added to a 22%by weight starch composition. The starch used was an oxidized starchsold under the trade name FLOKOTE 64 obtained from the National Starchand Chemical Company.

The solution was then applied to a paper web in bands, dried, and testedfor permeability. The resulting band permeability was 6 Coresta.

The treated paper was then wrapped around a column of a tobacco filler.The resulting smoking article was tested according to ASTM Test No.E2187-04 and according to the FASE Test. The following results wereobtained:

BASE PERMEABILITY (CORESTA) ASTM SE (%) FASE SE (%) 60 98 42

As shown above, the smoking article was very effective atself-extinguishing when placed on adjacent surface.

While the invention has been described in detail with respect to thespecific embodiments thereof, it will be appreciated that those skilledin the art, upon attaining an understanding of the foregoing, mayreadily conceive of alterations to, variations of, and equivalents tothese embodiments. Accordingly, the scope of the present inventionshould be assessed as that of the appended claims and any equivalentsthereto.

1. A smoking article having reduced ignition proclivity characteristicscomprising: a column comprising a smokable tobacco; and a paper wrappersurrounding the column of the smokable tobacco, the paper wrapperincluding discrete areas treated with a film-forming composition, thetreated areas being separated by untreated areas, the treated areashaving characteristics sufficient to reduce ignition proclivity, thefilm-forming composition applied to the paper wrapper comprising afilm-forming material and a polysaccharide.
 2. A smoking article asdefined in claim 1, wherein the film-forming material comprises analginate and the polysaccharide comprises a starch.
 3. A smoking articleas defined in claim 2, wherein the film-forming material comprises thealginate in an amount of from about 1% to about 15% by weight of thetreated areas and the starch in an amount from about 1% to about 20% byweight of the treated areas.
 4. A smoking article as defined in claim 2,wherein the alginate comprises sodium alginate.
 5. A smoking article asdefined in claim 2, wherein the starch comprises an oxidized starch. 6.A smoking article as defined in claim 1, wherein the treated areas havea diffusion capacity of less than about 0.5 cm/s.
 7. A smoking articleas defined in claim 1, wherein the treated areas are printed onto thepaper wrapper.
 8. A smoking article as defined in claim 2, wherein thefilm-forming material comprises the alginate in an amount of from about1% to about 10% by weight of the treated areas and the starch in anamount from about 3% to about 20% by weight of the treated areas.
 9. Asmoking article as defined in claim 1, wherein the treated areascomprise a plurality of discrete circumferential bands disposedlongitudinally along the smoking article.
 10. A smoking article asdefined in claim 9, wherein the bands are spaced from each other at adistance of from about 5 mm to about 50 mm, the bands having a width ofgreater than about 3 mm.
 11. A smoking article as defined in claim 1,wherein the treated areas have a permeability of less than about 30Coresta.
 12. A smoking article as defined in claim 1, wherein the paperwrapper has a basis weight of from about 18 gsm to about 60 gsm.
 13. Asmoking article as defined in claim 1, wherein the untreated areas ofthe paper wrapper have a permeability of greater than about 80 Coresta.14. A smoking article as defined in claim 1, wherein a burn-promotingagent is applied uniformly over substantially the entire surface area ofthe paper wrapper.
 15. A smoking article as defined in claim 14, whereinthe burn-promoting agent comprises of an acetic acid salt, a citric acidsalt, a malic acid salt, a lactic acid salt, a tartaric acid salt, acarbonic acid salt, a formic acid salt, a propionic acid salt, aglycolic acid salt, a fumaric acid salt, an oxalic acid salt, a malonicacid salt, a succinic acid salt, a nitric acid salt, a phosphoric acidsalt, or mixtures thereof.
 16. A smoking article as defined in claim 1,wherein the film-forming composition contains filler particles.
 17. Asmoking article as defined in claim 16, wherein the filler particlescomprise magnesium oxide, mica, kaolin clay, or mixtures thereof.
 18. Asmoking article having reduced ignition proclivity characteristicscomprising: a column comprising a smokable tobacco; and a paper wrappersurrounding the column of the smokable tobacco, the paper wrapperincluding discrete areas treated with a film-forming composition, thetreated areas being separated by untreated areas, the treated areashaving characteristics sufficient to reduce ignition proclivity, thefilm-forming composition applied to the paper wrapper containing fillerparticles, the filler particles comprising magnesium oxide, mica, kaolinclay, or mixtures thereof.
 19. A smoking article as defined in claim 18,wherein the film-forming composition comprises an alginate.
 20. Asmoking article as defined in claim 19, wherein the film-formingcomposition further comprises a starch.
 21. A smoking article as definedin claim 20, wherein the film-forming material comprises the alginate inan amount of from about 1% to about 15% by weight of the treated areaand the starch in an amount from about 1% to about 20% by weight of thetreated area.
 22. A smoking article as defined in claim 18, wherein thefiller particles have an average particle size from about 0.0001 micronsto about 5 microns.
 23. A smoking article as defined in claim 18,wherein the filler particles have an average particle size from about0.1 microns to about 3 microns.
 24. A smoking article as defined inclaim 18, wherein the filler particles comprise magnesium oxide.
 25. Asmoking article as defined in claim 18, wherein the filler particlescomprise kaolin clay.
 26. A smoking article as defined in claim 18,wherein the filler particles comprise mica.
 27. A smoking article asdefined in claim 18, wherein the filler particles are present within thefilm-forming composition in an amount from about 0.25% to about 15% byweight.
 28. A smoking article as defined in claim 18, wherein the fillerparticles are present within the film-forming composition in an amountfrom about 0.5% to about 5% by weight.
 29. A smoking article as definedin claim 18, wherein the untreated areas of the paper wrapper have apermeability of greater than about 60 Coresta.
 30. A smoking article asdefined in claim 18, wherein the treated areas have a permeability ofless than about 40 Coresta.
 31. A smoking article as defined in claim18, wherein the film-forming composition comprises a starch.
 32. A paperwrapper for a smoking article that provides the smoking article withreduced ignition proclivity characteristics comprising: a paper webdesigned to surround a smokable filler, the paper web including discreteareas treated with a film-forming composition, the treated areas beingseparated by untreated areas, the film-forming composition applied tothe paper wrapper comprising an alginate combined with a starch, thetreated areas having an inherent permeability of less than about 30Coresta, and a diffusion capacity of less than about 0.4 cm/s, the paperweb having a basis weight from about 18 gsm to about 60 gsm, thealginate being present in the film-forming composition amount from about1% by weight to about 15% by weight, while the starch being present inthe film-forming composition in an amount from about 1% by weight toabout 20% by weight.
 33. A paper wrapper for a smoking article thatprovides the smoking article with reduced ignition proclivitycharacteristics comprising: a paper web designed to surround a smokablefiller, the paper web including discrete areas treated with afilm-forming composition, the treated areas being separated by untreatedareas, the film-forming composition comprising a film-forming materialcombined with filler particles, the filler particles comprisingmagnesium oxide, mica, kaolin clay, alum, or mixtures thereof, thefiller particles being present in the film-forming composition in anamount from about 0.25% by weight to about 15% by weight, the paper webhaving a basis weight from about 18 gsm to about 60 gsm.
 34. A paperwrapper as defined in claim 33, wherein the film-forming compositioncomprises an alginate.
 35. A paper wrapper as defined in claim 34,wherein the film-forming composition further comprises starch.
 36. Apaper wrapper as defined in claim 33, wherein the filler particlescomprise magnesium oxide.
 37. A paper wrapper as defined in claim 33,wherein the filler particles comprise kaolin clay.
 38. A paper wrapperas defined in claim 33, wherein the filler particles comprise mica. 39.A paper wrapper for a smoking article that provides the smoking articlewith reduced ignition proclivity characteristics comprising: a paper webdesigned to surround a smokable filler, the paper web including discretetreated areas treated with a composition, the treated areas beingseparated by untreated areas, the composition comprising starch combinedwith filler particles, the filler particles comprising magnesium oxide,mica, kaolin clay, alum, or mixtures thereof, the filler particles beingpresent in the composition in an amount from about 0.25% by weight toabout 15% by weight, the paper web having a basis weight of from about18 gsm to about 60 gsm.
 40. A process for producing a paper wrapperhaving reduced ignition proclivity characteristics when incorporatedinto a smoking article comprising: applying to the paper wrapper afilm-forming composition at particular locations, the film-formingcomposition forming treated discrete areas on the wrapper, the discreteareas being separated by untreated areas, the film-forming compositioncomprising an aqueous composition, the film-forming compositioncontaining an alginate and a starch, the treated areas reducing ignitionproclivity of the smoking article incorporating the paper wrapper.
 41. Aprocess as defined in claim 40, wherein the alginate is present in thefilm-forming composition applied to the paper wrapper in an amount fromabout 1% to about 15% by weight, while starch is present within thefilm-forming composition in an amount from about 1% to about 20% byweight.
 42. A process for producing a paper wrapper having reducedignition proclivity characteristics when incorporated into a smokingarticle comprising: applying to the paper wrapper a film-formingcomposition at particular locations, the film-forming compositionforming treated discrete areas on the wrapper, the discrete areas beingseparated by untreated areas, the film-forming composition comprising anaqueous composition, the film-forming composition containing afilm-forming material and filler particles, the filler particlescomprising magnesium oxide, mica, kaolin clay, or mixtures thereof, thetreated discrete areas reducing ignition proclivity of the smokingarticle incorporating the paper wrapper.